First, a fun announcement: The second Bedtime Math book is coming, with all-new wacky math…and it’s kicking off with a big party for you! Bedtime Math 2: This Time It’s Personal launches March 11, and to celebrate we’re throwing a nationwide Glow-in-the-Dark Geometry Party that week at bookstores across the U.S. Kids will build giant geometric shapes out of glowsticks, then flick off the lights to see them shine. Over 130 stores in 41 states are taking part, and New York-area parties will have Laura there in person to read to the kids and sign books. Check the list here to find a party near you!

With that, let’s have a sneak preview from the book.

Underwear is that strange piece of clothing where no one sees it on us, but we still care what it looks like. We don’t want to wear underwear that’s goofy-shaped, or full of holes, or decorated with a cartoon character we haven’t liked in 3 years. That’s why things turn desperate when the laundry hasn’t been washed in a few days and we run out of underwear. How many pairs do we need to get through the week — and if we run out, how many people are we willing to tell?

Today is the 10th birthday of iTunes, the online store that lets you buy songs, movies, apps for your smartphone, videos…all kinds of stuff that you can enjoy on your phone or computer. Before iTunes, the only way we old-timers could buy songs was on something you could hold in your hand, like a CD, a tape cassette or a vinyl record. Or you could get songs electronically from various illegal websites, which was exciting but felt icky. So the idea that you could get onto your computer, buy any song you wanted (legally), and get it within seconds was mindblowing. iTunes opened with just 200,000 songs on it, all priced at 99 cents, and within just one week they had 1 million song downloads. As of today, iTunes has sold over 15 billion song downloads from a collection of 26 million different songs. Let’s just say, it takes far more than one person to listen to it all.

On this day in 1876, Alexander Graham Bell finally got his invention working: the telephone. It worked nothing like our phones today: the very first phones were sold in pairs, where each phone could call only that one other phone (you had to pick that other person carefully). Then came the “switchboard,” which let you call any other phone, but the “operator,” a phone company person in the middle of town, had to plug in wires to connect your call for you. Now we can call anyone anywhere on our own within seconds, and through the air. But that first phone, that first time talking to someone through a wire, must have looked like magic.

You’ve probably heard of biking to work, but biking at work is a whole other story. A recently invented work desk, called the WeBike, makes people work for their, well, work. As you sit at your desk, you pedal the bike, which generates the electricity to power your laptop, printers, phones, and other electronics. It seems like kids could use this thing even more than adults, to power all the batteries you need for your toys. And imagine if you had these bikes at school…could it do your homework for you?

Until pretty recently, when you wanted to find your way somewhere, you had to pull out a paper map, face it the right way, figure out where you were on the map, and then figure out how to get to your destination. Now we’ve taken all the fun out of it. With the digital maps on our smartphone and computer screens, you just type in your start and end points, and it draws the path you should take. Then geopositioning systems, or GPS, use satellites to find you and plop a blinking dot on the screen to show you exactly where you are. Now when taking a trip by car, thanks to GPS the days of crumpled maps are over. But as we’ll see here, when it comes to timing, sometimes the system doesn’t know everything.

One of the most popular and widespread toys ever invented is the Rubik’s Cube. The mission is so simple: just turn the rows and columns to swap around the pieces and get all six faces to be solid colors. And yet that turns out to be one of the hardest challenges out there – maybe because a 3x3x3 cube has over 43 quintillion possible line-ups of the pieces. Ever since the cube was invented in 1974, over 350 million of these puzzles have been sold; the Cube has inspired people to set all kinds of records, spawning speed cubers, one-handed cubers, and the real geniuses who study the cube, blindfold themselves and solve it from memory. To get a taste of the excitement, let’s look at the math behind cracking the code.

First, a really fun announcement: Bedtime Math is throwing a giant Pajama Party at the new Museum of Mathematics in New York! If you live in the NYC area or will be visiting, on Saturday Feb. 2 kids from ages 3-8 can come to MoMath in their PJs and play home-baked Bedtime Math games. You all get first dibs before this gets announced publicly, so click here to get the details and register!

And as long as we’re talking about math, it’s a great time to ponder the number 2013, our very cool new year. It’s the first year in a long time where all four digits are different – more on that below. Also, because the number 13 is prime – meaning it’s divisible only by itself and 1, and can’t be split into equal-sized groups – 2013 looks kind of yucky and prime also, but it actually isn’t. While the number 13 is considered unlucky by a lot of people, we’re thinking 2013 is going to be a good year.